176 SUMMARY OP CTKRBNT RESEARCHES RELATING TO 



monographically, and a plate is devoted to each. This will be a very 

 useful book, ;is ii includes literature, nomenclature, distribution, and 

 what is known as development, as well as a careful morphological 

 account of each form. The ten species are : Mackerel, Cod, Haddock, 

 Whiting, Plaice, Pleuronectes limanda, Solea vulgaris, Herring, and 

 Engraulis encrasicholus. 



Fishes of Panama Bay.* — Charles H. Gilbert and Edwin C. Starks 

 enumerate :S74 species, of which 4:5 are new. The new species are 

 described, and there are notes on many of those previously recorded. Of 

 the 374 species recorded from Panama, 204 are now known to occur in 

 the Gulf of California, and further exploration will certainly increase 

 the list of forms common to the two areas, which differ principally in 

 the greater development at Panama of Siluroids and Sciamoids. 



Much has been written concerning the close parallelism between the 

 fish faunas on opposite sides of the Isthmus of Panama, and the bearing 

 of this upon the question of a water-way formerly open between the two 

 oceans. The ichthyological evidence is overwhelmingly in favour of a 

 former open communication, which must have become closed at a period 

 sufficiently remote from the present to have permitted the specific 

 differentiation of a very large majority of the forms involved. It is 

 interesting to find definite evidence of the widely varying rates of 

 differentiation. Thus there are 54 identical species ; a larger number 

 have become distinguished by minute but constant differences, and by 

 imperceptible gradations we pass to widely divergent species. 



Sense of Hearing- in Goldfish.f — Henry B. Bigelow has made many 

 experiments, using an ingenious apparatus, to test the sense of hearing 

 in the goldfish {Carassius auratus, L.). He tested three sets : (1) nor- 

 mal fishes ; (2) those in which the greater part of the integument had 

 been made insensitive by cutting the fifth and seventh nerves, the lateral 

 line nerves, and the spinal cord close to the medulla ; and (3) fishes in 

 which the eighth nerve had been cut. 



Normal goldfishes usually respond in a definite manner to sound- 

 vibrations in water. Goldfishes in which most of the skin has been 

 rendered insensitive by cutting the nerves, and specimens from which 

 the ears, except the saccular portion, have been removed, still respond in 

 an essentially normal way to sound-vibrations in water. Goldfishes in 

 which the eighth nerves have been cut on both sides, thus eliminating 

 the sacculi and lagenaa as well as the rest of the ear, seldom or never 

 respond to sound-vibrations in water. Goldfishes possess the sense of 

 hearing, and the portion of the ear concerned with this sense is the sac 

 which probably represents the sacculus and the lagena of higher verte- 

 brates. 



Maldive Cephalochorda.J — G. II. Parker finds, in a collection made 

 by A. Agassiz in the Maldives, species representing the three genera 



* Mem. California Acad. Sci., iv. (1904). Contributions from Hopkins' Labora- 

 tory, xxxii. (1904) pp. 1-304 (33 pis.). 



t Ainer. Nat., xxxviii. (1904) pp. 275-84. 



t Bull. Mus. Corap. Zool. Harvard, xlvi. (1904) pp. 39-52 (2 pis.). 



